Checkerwork



July 22, 1930.4

H. A. BRASSERT ET AL CHECKERWORK Filed Jan. 18, 19,28

5 Sheets-Sheet 2 f l f/// 1f) All l 114// 5 Sheets-Sheet 5 Filed Jan. 18, 1928 H. A. BRASSERT ET AL cHEcKERwoRK July y22, 1930.

Patented July 22, 1930 l IUm'rlazn Isrnras- PATENT. OFFICE HERMAN A. BRASSERT, .ALBERT J. HULSE, AND CHARLES IV.I ANDREWS, OF CHICAGO, VILLINOIS, ASSIGNORS rIO H. 4 A.. BRASSERT & COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS C HECKERWORK Application filed January 18, '1928. Serial No. 247,570.

l This invention relates to a new and iniproved design of checkerwork for hot blast stoves, and more particularly to such a design adapted to substantially increase the heating 5 efficiency or transfer of heat in the checkers and to .increase the heating surface of a given stove. v A Hot blast stoves yfor heating the air for blast furnaces have been constructed with checkerwork of various design.V The usual checker employed in this country is built up out ofbrick placed on edge in such a way as to form-square openings. In former years hexagonal brick with round holes Were frequently used. Other special shapes have been employed in the past','generally with a view of stifening the checker column and prevent- Y 'ing shifting of the checkers through pres;

sure from the expanding combustion chamber Wall, but in every case the checker openings were of the same size from top to bottom and the heating surface was the same iny every cross section of the checkerwork throughout the height of the stove, whichyis usually from eighty to one hundred and ten feet. f

This uniform construction has the disadvantage that the top checkers do most of the Work of lieat exchange, 'both during the vperiod of h ating and of giving off heat to the blast.` he top checkers are heated to very nearly the same temperature as the combustion chamber, that is, to'a bright red heat,

and the checkers about thirty feet down are heated to a dull red heat. 4Below this point `the checkers remain black and the lower l half of the checker column does but very l-ittle work. In otherwords, the temperature at the top of the checkers is usually around 40 2000o F thirty feet down approximately 1200o and fifty feet down about 800, or very close tol the usual chimney temperature of 600. v

`There are two reasons for the ineilicient work performed bythe lower portion of the lcheckerworln One reason vis that the heat exchangel is more rapid and more penetrating the higherthe difference l1n temperature of the heat exchanging mediums. In other words, the-heat transfer is a function of the heat head, but it is also a function of the velocity of the gases. When the stove checkers are of equal design all the Way through the checker column, the combined open area through the checkers being the same from top to bottom, 'the velocity ofthe hot gases is very much greater at,the top of -the checkers than at the bottom, also the velocity of the cold blast is very much greater at the top of the checkers than at the bottom. .Ifthe temperature at the top of the checkers is 2000o and at the bottom 500, the ratio of velocities is approximately two and one-half to one. In the case of the cold blast, the difference is even greater, being more nearly three to one when high blast temperatures are carried. e

IVe have invented a type of chcckerwork which permits of a decrease in the size of the checker openings in the bottom part of the stove as compared to the top part of the stove, with the result that the velocities are equalized to whatever extent'desired. Since it would require too many different sizes of brickto reduce the sizes of the flues continually from the top down, layer .for layer, We preferably make the gradation in' three or four steps' only. Our checkerbrick is' octago- ,nal in shape, the brick having eight sides of which four are much longer than the other four. The octagonal brick have round holes in the center. The four longer sides form the Wallsof the square checker vopenings between the octagonal brick, as shown on the drawing. For manufacturing reasons these brick maybe split vertically through the center openingsand made as two separate brick. All vthese brick may, however, be readily manufactured as a continuous ribbon of clay forced from the dies of a usual brick or tile machine. e

, We' are aware that octagonal brick have been used before in such a way as to leave square openings between them, butsuch brick had substantially equal sides. The advantage of making the sides which form the square openings longer is that the brick areas between each tworound openings are reduced. It will be noticed that with the octagonal design of checker brick the center portion o f the brickwork between two round openings is furthest removed'from the walls of t-he checker ues and therefore the least accessible to the flow of heat and the least useful for heat transfer. By lengthening the walls of the square openings, this area is sub- A'stantially reduced, therefore the checkerwork becomes relatively more efficient as compared to checkerwork built up with octagonal brick having substantially equal sides. such as have been heretofore used.

In order to reduce the cross-sectional area of the checker openings from the top to the bottom, we 'may employ brick with thinner walls in the'top section of the checker column and brick/withl heavier walls in the bottom section, grading this construction as stated before by having preferably three or four sections in the checker column, the bottom section ofthe column havingwalls 2% inches thick, the centersection walls 2 inches `thick and the top section walls 1% inches thick, resulting in the openings in the top section being 51/1 inches and the center section 4% inches and the bottom section 3% inches in diameter. The long sides of the octagonal brick may be curved 'or angular with the result that the square openings will have curvedl or angular Walls. This results in a decrease in the area of the square openings. designs have the further vadvantage .of

strengthening the checker `column in the bottom sections, tlie heavier wall thickness rendering the structure more massive and morev rigid andalso easier to support on the arches below due tothe heavier walls at the pointof contact with the arches. A

Another method of increasing .the velocities in the bottom section of the stove as com pared to the-top sections, is to insert fillers in the lower sectionsto produce thedesired gradation. IVe insert loose brick as fillers in the square and round openings in the bottom. sect-ion. The corners of these loose brick are' therefore form a more stable structure. It is desirable to have the same storage of heat in the fillers as well as in the walls of the checkersper unit of surface. lFor instance, if the wall thickness ofthe checkers is two inches, that of the filler should be two inches alsol in order to transfer the heat in the same unit of time. 'The sides of these brick may be rounded, triangular or corrugated in form. The two sides of the bricks may be formed differently and superposed brick turned end for end so asto expose different forms of sidesin lthe passageways. The flow will be 4broken up and large surfaces brought in'contact with the gases.

These filler brick should be staggered in successive vertical sections of the structure. This has thev advantage of forcing the gases as well as the hot air to zigzag through the checkers and to impinge against the lower surfaces in the case of the gas, and in the upper surfaces in the case `of the airof the filler brick. The zigzag course and the impingement will cause turbulence of the gas and air, the lswirls and eddies compelling positive impingement against the side walls and greatlyfincreasing the heat transfer in accordance with well established laws. In

the "center section we may put the insert in the square openings only and may place no fillers at all in the top section of the checkerwork.

Another form of construction consists in section would be thickest, with thinner` bricks effective passage area for gases and air.

The bricks in the bottom tier are preferably supported by metal bars which are made 'from heat resisting steel. These bars preferably rest immediately on top of the arches or cross walls and extend clear across the checker area from combustion chamber Wall to side wall. In order to decrease the movement caused by expansion and contraction, these bars are preferably made in one or more sections with interla'cing joints. This method of support is new and can be em'- ployed as Well for the fillers as for the checkerwork. If metal bars are employed for supporting the fillers only, they may be rested on va bottomlayer ofcheckers, these thenv having no l'illers.' 4 p Itis an object of the present invention to provide a new and improved design of checker brick and checkerwork construction. p

It is a further obj ect to provide a brick and construction adapted to substantially lincrease the heating efficiency or transfer of heat over that of present checkers of usual construction.

It is an additional object to provide a checker brick and construction which Will increasethe heating surface of a given stove.

and flow to some extent, thus reducing the l It is also an object to provide a checker I and installation.

Other and further objects will appear as the description proceeds.

lVe have illustrated certain preferred embodiments' of our invention in` the accom'- panying drawings, in which Figure l is a fragmentary horizontalsection of one form lof construction;

Figure 2 is a similar View of a modified and adapted for commercial manufacture form of construction;

Figure 3 is a perspective view of one of the' bricks; y

Figure 4 is a view similar to Figure 1 showing a further modification;

sections showing further forms of loose' brick construction; and

Figure 14 is a vertical section through the form of construction shown inFigure 2.

Referring first to Figure 3, the preferred `form of brick is octagonal in form having a central opening 11 which is circular in cross section and passes through the brick from end to end. rlhe four shorter sides 12 of the brick are placed alternately between the longer sides 13. 'It Will be noted that t-he sides 13 exceed in width the sides 12 by more than onethird of the width of thelatter sides. Also any two opposite sides 12 are further apart measured diametrically across the brick than any two opposite sides 13.

The brick shown in Figure 3 is provided upon its lower face with notches 14 adapted for the passage ofthe bar 1'5, the use ofwhich will be explained in detail hereinafter. `It will be understood that only a portionof the bricks will be formed with the notches 14, the majority of them being without these notches and identical upon either end.

In making up the brickwork a plurality of the brick 16 of Figure 3 are placed together with their narrower sides 12 in contact, as clearly shown in Figures 1 and 2. This form of building up the brick causes their longer sides 13 to be spaced apart to form the Vertically extending passageways 17. The sizeof the central passageway 11 in some of the bricks used in the lower courses of the structure may be reduced as shown by the circular lines 18 appearing in Flgure 1, and the pas- .sages 17 may be 'similarly reduced as shown at A17. l .l

In the form of construction shown invFig-2 ure 2, the special loose brickl 19 are placed in the passageway 17, these bricks having their portions 20 formed to conform substantially to the contour of the corners of the passageways in which they arediagonally placed. The filler brick are so designed and sized as to fit sufficiently loosely to allow for ordinary variation in Size in manufacture. -brick may preferably be so proportioned as lto have a thickness substantially equal to the thickness of the walls surrounding the passageways. The brick'v19 may be placed in either diagonal direction, as shown in Figure 'The filler.

2, and in the preferred form of construction a number of successive bricks will be placed extending in lone direction in the column and then a series of superposed brick will be placed extending in the opposite direct-ion in angular relation to the first series. These bricks serve to divide the passageways 17"and to decrease the effective passage area of such passageways. It will-be noted that the thickness 'of the brick 19 may be substantially that existing between the walls 13 and the central passageway 11 of the brick 16. `Thus both the loose brickand the brick making up the body ofthe checkerwork will serve wlth equal facility for taking up heat from the blast gases and discharging this heat to the incoming hot blast. The brick 21 are similarly located in passageways 11 formed in the brick 16. T hesebrick 201 may have their side edges'I K 22 arcuate in form to substantially conform Vto the contour of the circular passage in' which they are placed. It will be understood that in the complete construction of a hot blast stove bythe use of the vform of construction shown in Figure 2, the brick 19 and 21 will.

preferably be placed in all passages in the lower portion of the stove.nl The effective passage area for the gases will thus'be reduced at this point where the volume ofthe hot blast gases has been reduced to the 'greatest extent by having given up their heat to the checkerwork. Similarly, these ilues of least area will receive the comparatively cold incoming hot blast air whenits volume is least before it has been expandedby the heat picked up from the checkerwork. In the intermediate vertical sections of a stove the brick may be lplaced in only one set of passageways, that is either the passageways 11 or,17. Preferably where this form of construction is used, they will be left out of the p assageways 11 and placed only in the passageway 17. At this'v point in the stove, the heat gases will have been partially reduced in vol-ume land the hotblast air will have been partially expanded in volume and the additional space provided by the removal of part of thejbrick will provide such an area asI to maintain 'the velocity'of How of both gas andV hot blast air approximately uniform." In the topmost ortion of the stove -no bricks will be place in either set of passages. Here both the blast gases and the hot blast air are at their greatest temure 2, the loose brick are shown as of greater perature and require the greatest passage area' if their velocity is to be maintained. y In the form of construction shown in Figsize in the lower section of the checkerwork than in an intermediate portion. By this means brick will be located in all vertical passageways .both in the bottom and intermediate sections.

ever, of the desired greater reduction in area of the passageways inthe lower section and lesser reduction of area in the intermediate section. It will be understood that, if desired, brick of more than two sizes may be used, so that there may be more than two sections with brick of less thickness in the sections as the sections approach the top section,

which section will preferably have its pas-' sageways without loose brick.-

The forms of construction shown in Figure 1 will take care of the desired reduction in area to same extent by using brick having interior passageways 11, gradually decreasing in size as the brick approach fthe bottom of the stove. It will be understood that the passageway 11 will not be tapered ,in individual brick nor will there be a continuous small variation, but normally brick having differ- .ous vertical sections of the stove. ly, the area of passageways 17 will be re-4 duced, as shown in the figure.

ent sizes of passages will be used in the vari- Similar- In the vform of construction shown in Figure'4, the brick 24 are provided with narrow contacting sides 25 similar to the sides 12 of the brick 16 of Figure 3. The sides 26 of the brick project into the passageways 27 and reduce the effective area of these passageways .while increasing the surface area of the passageways contacting with the gases owing through them. The central passageways 28 inthe brick 24 have their surfaces corrugated, as shown at 29, in order that the area v of contact with the gases may be increased.

In Figure 5 there is showna form of con-A struction quite similar to Figure 4, with the exception that the sides 30 of the brick 31 are more roundedthan the similar sides 26 of the brick 24. The passages 32 are thus greaterin area than the passages 27. Theapassages -33 extending through the brick 31, have their be used for the lower lportion of a stove, the

form of construction shown in Figure 5 may be used for an intermediate portion of a stove,

` The variation in the thickness of the loose brick will take4 care, Ahowand the form of consi ruction shown in Figure 2 may be used for the upper portion of a stove. 'In this case `it will be understood that there will be no loose brick in the passageways of the stove.4

In Fi ure 8 is shown the form of the meeting sur aces of superposed brick which are turned at right angles to each other." In order to avoid the great restriction in area available for flow at this point if the brick were of usual type, the meeting faces of the brick are cut away as shown at 45. The brick thus permit free passage of gases as they are cut away except upon the central portion where the brick contact. It will be understood that only one form of special brick will be necessary for this purpose as the two meeting brick are identical inform, one being merely inverted relative to the other.

In the form of construction shown in Figure 9, the loose brick 46 are provided with concave portions 47 and convex portions 48 which increase the contact area for heat transfer and also form passage spaces without narrowicorners which would be to some extent dead air spaces.v In Figure 10 the brick 49 is generally similar to that of Figure 9 but one side 50 is Vcorrugated which increases the contact area and also assists in causing'swirls which will increase the contact and heat transfer. Alternate bricks or o-ccasional bricks ma be turned'end for end so that some sides will be smooth and others corrugated in the same line.

In Figure 11 we have shown a form of loose brick 51 in the passageways 11 having angular sides 52. Lower brick 53 are shown having angular sides projecting further into the passageways. Similar brick 54 are placed in passageways 17 and brick of greater thickness v55 are shown below the brick 54. lVhile brick of only two thicknesses have been shown in this figure, it willbe understood that a large number of different thicknesses of brick ofjthesame general contour may be used if desired. The brick 55 of Figure 12 have the convex portions 56but have no concave portions as shown in Figure 9. In Figure 13 the brick 19 in the passageways 17 are similar to those of Figure 2 and the brick 22 in passageways 11 are also similar to 'Figure 2. Instead, however, of a number of brick heilig placed in one direction and then others at right angles, in thisform of construction the brick 22 are turned slightly relative to each other, forming a gradually twisting passage for gas flow. It will be'understood that these foi-nis are illustrative and that many other .forms of 1 through special blocks provided with notches 14 in the lower portion of the stove. In the preferred form of construction, there Will be no loose brick in the lowermost course of'` v brick 16 and the bars 15 will restl on top of the lowermost' course fitting in notches 14 in the bottom of the next course of brick;A Additional sets of rods may be placed at verticallyspaced points in the structure sothat the looseJ brick will not all be directly supported from the bottom. i

`In order to increase the stability of the structure part size brick 16 will be provided,

of such brick in the lower l5 that is, brick of part the height. By the use l portion of the structure, the brickwork may be built up so that theuhorizontallyl extending joints between superposed brick will be located in different planes in adjacent brickl columns. By means ofthis breaking of joints the structure will be rendered more'stable, as it will be impossible forany one horizontal tier of brick to move relative to the tiers above or below. The breaking of horizontal joints also facilitates the erection of the structure.'

shell.

The vmethod of supporting. the lowermost brick has been indicated in Figures 6 and 7. rluhe central portion of the stove'is shown at 36 and the outer shell at 37. The supporting l arches 38 extend radially outward from the central portion to thev brick lining 39 of the These arches 38 supporta plurality of metal supporting beams 40. These beams having .lapped `figure, the special brick 16`will lICO-are made up of a'plurality of sections joints '41. In so far as possible the sections and lapped joints are made such length that the lapped ends of the adjacent bar rest upon a brick supporting arch 38. As shown in the lower portion of Figure 6, the brick 16 rest directly onthe metal portions 40. -These beams are of such size j and so spacedasfto lbe of all of the vertically extending openings 11v substantially clear and 17 It will be noted that as shown in the preferably not be broken to ill .up the stove but bricks 42 of usual rectangular shape will be used to fill up irregular portions of the brickstruc- 4 ture.

While We have described several preferred designs of brick and constructions for carryf ing out our purpose of equalizingthe veloci- 'ties of llow of heat exchanging gases through the checkerwork, there are many further Vdesigns of brick and of checker construction whichare capable ofcarrying out our objects and we contemplate such further changes and modifications as come within the' spirit and scope of the appended claims. l

' Our constructions also` serve to increase the totall eilective heating surface as Well as to equalize velocities of flow and in addition provide structures of greater strength and stability than usual types of construction.'

The brick and methods of construction are -simple design and are capable of commercial manufacture and installation.

e claim: 1. A checkerwork construction comprising a plurality of brick `laid in superposed tiers continuous vertically extending passageways throughsaid brickwork, and separate means insertedin said passageways whereby the effective area of said passageways for the passage of gases issuccessively reduced.

2; A checkerwork construction comprising a plurality of brick laid in superposed tiers, continuous vertically extending. passageways through said brickwork, and separate meanswhereby the effective area of said passageways for the passage of gases is greatest in the upper tiers of said construction, less inintermediate tiers andleast in the lowermost tiers. f

3. A checkerwork construction comprising aplurality of brick laid in superposed tiers, vertically extending passageways extending through said checkerwork, and a columnof brick loosely placed in certain of said passageways to divide the passageways, said brick fitting suiciently loosely to allow for ordinary variation in size in manufacture.

4. A checkerwork construction comprising a plurality of'brick laid in lsuperposed tiers, vertically extending passageways extending through said checkerwork, and a column of Ybrick loosely placed in certain of said passagewaysto divide the passageways, said vbrick fitting sulliciently loosely to allow for ficiently loosely ,to allow for ordinary variation in size in manufacture, said loosely placed brick being in more of said passageways in the lower portion of the structure than in a superposed portion.

6. A checkerwork construction comprising a plurality of brick laid4 in superposed tiers, vertically extending passageways extending through said checkerwork, and brick loosely placed in certain of saidpassageways to divide ythe passageways, said brick littmg sulliciently loosely to allow for ordinary variation 1n size in manufacture, said loosely placed brick being of greater thickness in said passageways in the lower portion of the structure than in fa superposed portion.

in certain of said passageways to di- 7. A checkerwork construction comprising a plurality of brick of generally similar conthrough, said brik being laid in superposed a plurality of brick of generally similar con-' sageways, said brick itting sufficiently' loosely to permit their ready insertion with normal variation in size of manufacture, said brick `being of greater thickness in the lower tiers than in intermediate tiers and no brick being placed in the passageways in the uppermost sets of tiers. i

8. A checkerwork construction comprising tour, said individual brick having vertically extending passageways extending therethrough, said brick being laid in superposed tiers with additional passageways formed therebetween, and loosely placed brick located in the tiers of brick in both said sets of passageways, said brick fitting sufficiently loosely to permit their ready insertion with normal variation in size of manufacture, loosely placed brick being of less thickness in the passageways in vertically intermediate sets of tiers than in the lower tiers, and no brick in the passageways in the uppermost sets of tiers, certain of the brick in each passageway being placed in angular relation to other brick in the same passageway.

9. A checkerwork construction comprising a plurality of brick, said construction having therein a plurality of vertically extending passageways, additional special brick placed in columns in said passageways, said brick extending diagonally of the passageways and dividing said passageways, and certain of said brick being placed in angular relation to other of said brick.`

10. A checkerwork construction comprising a'plurality of brick, said construction having therein a plurality of vertically extending passageways, additional special brick placed in columns in said passa geways.I lsaid brick being formed with vertically extending faces adapted to substantially conform to the contacting portions of the pas` sage walls.

l1. A checkerwork construction comprising a plurality of brick placed in superposed courses, a support construction below said brickwork, and a plurality of metal members lsupporting the brickwork from said support construction, said metal members being short in length and adjacentmembers in the same line having overlapped ends, said overlapped ends being located above element-s of the support construction. l

, 12. In a checkerwork construction, a -plurality of brick laid in superposed tiers, vertically extendingpassageways through said brickwork. brick placed in certain of said passageways and metallicmembers carried by the first named brick and extending across said passageways to supportthe last named brick.

13. In acheckerwork construction, a plubrick, metal members supported by certain of said brick extending across certain of the passageways, and additional brick placed within certain of said passageways andy supported on said members.

15., In a checkerwork construction, a'plurality of brick having vertically extending passageways formed within the brick, said brick being built up' in superposed tiers to form additional passageways between the brick, metal members vsupported by certain of said brick extending across passageways both in said brick and between said brick, and additional brick placed within said pas: sageways both `in said brick'and between said brick and supported onsaid members.

16. Checker bricks yadapted to' engage other bricks in angular relation, said brick having reduced engaging faces and having portions of the adjacent faces cut away upon an angle. to facilitate passage of gases at the plane of 'the.engaging faces.

17. In a checkerwork construction, a plurality of brick .forming vertical passageways, other brick located in said passageways, certain of said other brick being in angular relation to each other, said brick havingreduced engaging faces and the adjacent surfaces of said angularly 4related brick being cut away to facilitate flow of gases through said passageways at and adjacent the plane of the meeting faces.

18. A checkerwork construction comprising a plurality of brick placed in superposed courses, a support construction below said brickwork, and, a plurality of metal members supporting the brickwork from said support construction, said metal members being short in length and adjacent members in the same line having overlapped ends.

19.` In a checkerwork construction, a supporting structure, a plurality of brick laid in superposed tiers, vertically extendin passageways through said brickwork, ricks placed in certain of said passa'geways and metallic members extending within the contour ofthe passageways in the lbrickwork and support-ing the brick placed in said passageways.

20. A checkerwork construction .compris ing a plurality of brick placed in superposed courses, a support construction below said brickwork, and a plurality of metal members supporting the brickwork from said support construction, said metal members being short in length and placed in aligned relation in subst ntially parallel lines.

Signed at C "cago, Illinois, this 16th day of January, 19 y8.

ERMAN A. BRASSERT. ALBERT J HULSE. CHARLES W. ANDREWS. 

